Infestation potential of 16 cultivars of flax, mustard, rape, sunflower, millet, and clover seeds to five common species of stored-product insects was determined. When multiplication was used as a criterion, whole seeds were resistant to insect attack although minor infestation occurred on certain cultivars. Although some species of insects could complete development on certain cultivars, few could reproduce well on clover and mustard cultivars. Oilseeds were more susceptible to Oryzaephilus mercator than to any other insect species. Cryptolestes ferrugineus, which thrived on the millet cultivars Crown and Siberian, neither reproduced nor completed development on any of the oilseed and forage cultivars. All cultivars of crushed Noralta, Raja, and Redwood flax were susceptible to: O. mercator, O. surinamensis, and Tribolium castaneum; Echo and Target rape only to O. mercator; Armavirec, Krasnodarets, Mennonite, and Peredovic sunflowers to all insects except C. ferrugineus; and Crown and Siberian millet to all insects. Tribolium confusum reproduced only on sunflower and millet cultivars. The potential danger of stored oilseeds in Western Canada from a new pest, O. mercator, was evaluated.